RAAL Requisite CA-1a FilterSet
The RAAL CA-1a Neutral FilterSet package contains two complete filtersets for both earpads. Each filterset contains filters with sample rates from 44.1 kHz to 352.8 kHz and packaged as a .zip file that can be used in most convolvers, like Hang Loose Convolver and Roon for example. Mono 352.8 kHz mono filters are also included for HQPlayer.
FilterSet Free Trial Offer: Download the Hang Loose Convolver 14-Day Free Trial software. Specify the RAAL CA-1a Neutral FilterSet in the Order Notes at checkout.
Full Product Description
Frequency Response Measurement & Correction
Closed earpads
Open earpads
The RAAL requisite CA-1a is a ribbon headphone. Depending on which earpad is used, produces a significantly different sonic signature. While the closed earpads produce a reasonably smooth response up to 1 kHz, there is a significant wide band -8 dB dip in frequency response from about 1.5 kHz to 5 kHz. This results in a very dark sound.
While the open earpads aren’t as dark sounding, there is a lack of deep bass response with a 1.2 kHz peak and then another -6dB dip in frequency response between 1.5 and 3.5 kHz, right where out ears are the most sensitive. The rising narrow band peak at 5 kHz gives the headphone the impression of being a bit brighter than the closed earpads, but still very midrange-y sounding.
With the addition of the phase response chart, the CA-1a have phase issues that obfuscate the clarity and depth of field that these headphones are capable of.
Engaging the high-resolution convolution filter is indeed a “night and day” difference in sonic signature of these headphones. With the convolution filter engaged, using either set of earpads, the response is ruler flat from 15 Hz to 5 kHz +- 0.5 dB. The convolution filters fully optimize the ribbon design and manufacture of these headphones.
Bard Geesaman (verified owner) –
Headphones were dreadful before applying these filters. Now sound as good as any I have listened to. I was amazed to hear now much soundstage and imaging improved.